Electric motor starter



p 1954 J. w. BOERGER ELECTRIC MOTOR gTARTER 2 Sheets-Sheet 1 Filed Dec. 21, 195].

. INVENTOR JULIUS W. BOERGER ATTORNEYS P 1954 J. w. BOERGER ELECTRIC MOTOR STARTER 2 Sheets-Sheet 2 Filed Dec. 21, 1951 I NV EN TOR JULIUS W.BOERGER AT TORNEYS Patented Sept. 14, 1954 ELECTRIC MOTOR STARTER Julius W. Boerger, Racine, Wis.,v assignor to. Allover Manufacturing Company, Racine, Wis., a

' corporation ApplicationDeccmber 21, 1951, Serial No. 262,784

, Claims.

1. This invention appertains to, electric motors of the smalli, compact type. which are particularly employed for hand tools, such as hair clippers,

dryshavers and the like;

One of the primary objects of this invention is to provide. a novel and simple means for initially rotating the armature of an A. C. or D. C. motor from the finger piece of the switch of the motor, as the switch is moved to its: circuit closing position, to insure. the instantaneous and proper starting of the motor.

Another salient object of the invention is the provision of a toothed starter slide plate or link mounted. for limited sliding and swinging movement in the housing for the motor, and operatively connected for movement with the switch lever or thumb-piece of the circuit closer adapted to engage a spur gear or the like secured to the armature when the switch lever is moved to its circuit closing position for rotating the armature shaft, the construction being such that upon the returnmovement of the. switch to its circuit opening position, the toothed starter slide plate will be moved away from and. out. of contact with the spur gear.

A further important object of the invention is the provision of novel. means for insuring the proper positioning of the toothed starter slide plate for engagement with the spur gear on the armature during movement of the switch to its circuit closing position, and for insuring the movement, of the toothed starter slide plate from contact with the spur gear. upon movement of the switch to itscircuit opening position. I

.A still further object of the: invention is the provision of so-forming the parts of the starter and switch relative to one another that a minimum amount of space will be occupied within the case or housing for. the motor.

With these and other objects in View, the invention consists in the novel construction, arrangement and formation of parts, as will be more specifically described and claimed, and illustrated in the accompanying drawing, in which drawing,

Figure 1 isa top plan view of an electric tool showing-the invention incorporated therewith, the top wall of the case for the motor being removed to illustrate the starting mechanism and switch.

Figure 2 is a fragmentary longitudinal sectional view through the motor and case, taken on the line 2-2 of Figure 1, looking in the direction of the arrows, the view showing the arrangement of the starter slide plate relative to the starter gear wheel.

Figure. 3 is av transverse sectional. view through the motor and casing. taken. on the line 33 of Figure 1,1ooking in the direction of. the arrows.

Figure 4 is a view similar to Figure 1-, but showing the switch in its circuit closing, position, with the starter slide platev moved beyond and to one side oi the starter gear wheel.

Figure 5: is: a, fragmentary detail sectional view taken on the line i-Ev of, Figure 4, looking in the direction of the arrows showing the engagement of. the bridge stripwith the switch contacts of the motor- Figure 6 is a detailfrag-mentary longitudinal sectional view taken on the line 6--B of Figure 4, lookingin the direction of the arrows and illustrating the. mounting of the starter slide plate within the case of the motor and its connection with the movable part of the switch.

Figure 7 is a detail. perspective view of the starter slide plate removed from the motor.

Referring to the drawing in detail, wherein similar reference characters designate corresponding parts throughout the several views, the letter T generally indicates a portable hand tool, and for the purpose of illustration, the same has been embodied in a hair clipper. The hand tool T includes a case. or housing Iii for receiving an electric motor II, which actuates the movable cutter blade 12 of a cutting assembly [3. This cutting assembly [3 also includes the stationary comb plate 14 carried by the case or housing Ill.

The electric motor I I can be of the same type and character as shown in the pending applicationiof Julius W. Boerger, Serial Number 107,403, filed July 29, 1949, now Patent No. 2,586,415, issued; February 19;. 1952; Hence, the motor will not be described" in detail, but. the same includes a frame [5, the opposite ends of which carry the field windings l6 and ll The frame [5 intermediate the fiel'd' windings Hi and Il carries transversely extending top and bottom frame plates It and i9. These bridge frame plates [8 and i9 rotatably support the shaft 2'0 of the armature 2 l The armature shaft 2% actuates the movable cutter blade I2- through the medium of an oscillating lever 22'. Thelever 22 is mounted for swinging movement on a pin' 23 carried; by the frame ll of the motor and the inner end of the lever 22 is bifurcated, as at 2'4", for straddling an operating cam 2'4" rigidly secured to the armature shaft .2 0..

Other features of the motor are not important to. the present invention, but it is to be noted that the motor ll includes a switch mechanism 2.5. for opening and. closing the circuit to the motor, whichdoes form a part of this invention 3 in conjunction with the novel starting mechanism 26. These features will now be described in detail.

The switch mechanism 25 includes a stationary disc 21 formed of insulating material, rigidly secured to the top frame plate l8, such as by screws 28. The armature shaft 28 rotatably extends through this disc for a purpose, which will later appear. Between the frame plate l8 and the disc 21, is preferably disposed a supporting plate 29, which is also formed of insulating material and this plate 29 extends a material distance beyond the disc 21. Mounted for turning movement on the disc 21 and on the plate 29 is an annular switch plate 38, also formed of insulating material. The inner edge of the annular plate 38 snugly engages the outer periphery of the disc 27. Formed, on the annular switch plate 38 is the radially extending thumb or finger piece 3|, so that said switch plate can be turned on the disc 21. This thumb or finger piece 3| protrudes through the case or housing Riveted, or otherwise firmly secured to the disc 21, are spaced contact pieces 32 and 33. Each of these pieces includes an arcuate attaching portion 34 and an outwardly extending contact arm or finger 35. It is to be noted that the attaching base portions 34 extend over the annular switch plate 38 and function to hold the switch plate against displacement. Mounted for movement with the switch plate 38, is an electric conducting bridge strip 38. One end of this bridge strip extends under and is in constant electric contact with the contact piece 33, and when the switch plate is turned to its circuit closing position, the bridge strip rides over and electrically engages the contact piece 32 to bridge and electrically connect the contacts 32 and 33 of the switch mechanism. Obviously, the contact pieces 32 and 33 are properly electrically connected to the desired motor parts. As shown in Figure 1, the finger piece 3| is at the left and the bridge strip 33 is out of contact with the contact piece 32. Consequently, the circuit to the motor is open. In Figure 4, the thumb piece 3| is shown at the right, with the bridge piece 38 in electrical engagement with the contact pieces 32 and 33 and consequently the circuit is closed.

Now referring to the starting mechanism 28, the same includes a starter wheel 31 rigidly secured to the armature shaft 28 adjacent to the disc 21. This starter wheel can be in the nature of a ratchet, if so desired, but preferably, as

shown, in the nature of a spur gear or pinion.

At one side of the starter wheel 31 is slidably and pivotally mounted a starter slide plate or link 38, best shown in Figure 7. The starter plate 38 is guided in its movements by a supporting bracket 38. This bracket includes a foot 48- which is rigidly secured to the top frame plate I8 at one side of and below the switch plate 38. Formed on one end of the foot 48 is the upwardly and then outwardly bent arm 4|. This arm is in turn provided with a longitudinally extending guide slot 42. Formed on the arm adjacent to the inner end thereof is the upwardly extending finger 43 which cooperates with a part of the slide starter plate 38 as will be later set forth.

The starter slide plate 38 has formed on one end thereof an inwardly directed, T-shaped guide head 44, which lies below the arm 4| of the guide bracket 39. The slide starter plate at the point of the formation of the head 44 thereon extends through the slot 42 of the arm and the slide plate 4. 38 moves over the arm 4|. A sufficient play is provided between the starter slide plate 38 and the walls of the slot 42 to permit a limited swinging movement of the plate 38 on the guide bracket. Formed on one edge of the plate 38 adjacent to its inner end is a laterally extending tooth 45, which is adapted to engage the teeth of the starter wheel 31, as will be also later set forth. Formed on the opposite edge of the plate 38 and at one side of the tooth 45 is a cam wedge surface 48, which engages the finger 43 during a part of the movement of the slide plate. The inner end of the slide plate is pivotally and slidably connected to the finger piece 3| of the switch plate 38 by means of a pin 41. The pin is carried by the finger piece 3| and extends through a transversely extending slot 48 formed in the inner end of the starter slide plate 38.

At one side of the finger piece 3|, the movable switch plate 38 is provided with a peripheral cut out portion or notch 48 defining a lift shoulder 58 for the starter slide plate 38, when the finger piece 3| is at the extreme right (see Figure 4) and the switch is in its circuit closing position.

In operation, considering that the switch is in its circuit opening position (see Figure 1) it will be seen that the starter slide plate 38 is at the extreme left and the finger 43 is adjacent to the top of the cam surface 48 and the finger functions to hold the plate 38 in an inward position with the tooth 45 ready to engage the teeth of the starter wheel 31. When it is desired to start the motor, the finger piece 3| is moved to the right (see Figure 4) and the bridge strip 36 is brought into contact with the contact piece 32, as well as the contact piece 33. During the movement of the switch plate 38 the starter slide plate 38 is moved therewith and the tooth 45 will engage the teeth of the starter wheel 31 and rotate this wheel and the armature 2| of the motor by the time the bridge strip makes its contact with the contact piece 32. Hence, the motor is insured of proper starting upon the closing of the circuit. As the finger piece 3| reaches its extreme position to the right, the shoulder 58 of the movable switch plate 38 moves into engagement with the starter slide plate 38 and pushes the slide plate outwardly on the finger piece 3| which is permitted due to the position of the slot 48, and consequently the tooth 45 is moved beyond the starter wheel 31. When it is desired to stop the operation of the motor, the finger piece 3| is moved to the left (again see Figure 1) and during this movement the starter slide plate will also be returned to its left hand position and the cam surface 46 will ride against the finger 43 and the finger will force the slide plate inwardly so that the tooth 45 will be in position for turning the starter wheel and the armature when the finger piece is again moved to the right.

From the foregoing description, it can be seen that I have provided an exceptionally simple and durable mechanism for turning the armature shaft of a motor during the movement of a switch to its circuit closing position. Due to the formation of the starter slide plate and its guide a compact structure is had which will easily fit within the case or housing |8.

Changes in details may be made without departing from the spirit or the scope of this invention, but what I claim as new is:

i. In a starting device of the character described, a rotatable shaft, a movable switch plate having an outwardly extending finger piece; a

starter wheel rotatable with the shaft, a starter slide plate movable tangentially of the starter wheel, a guide bracket slidably and pivotally supporting the outer end of the slide plate, means pivotally and slidably connecting the inner end of the slide plate to the switch plate, said slide plate having an inclined wedge surface and said guide having a finger disposed in the path of said wedge surface for moving the slide plate toward the starter wheel when the switch plate and finger piece is in one of its two positions.

2. In a starting device of the character described as defined in claim 1, and means on the switch plate adjacent to the finger piece for moving the slide plate beyong the starter wheel when the switch plate and finger piece is in the other one of its two positions.

3. In a starting device of the character described as defined in claim 2 and said last named means including a shoulder on said switch plate movable into engagement with the slide plate.

4. In a starting device of the character described, a rotatable shaft, a turnable switch plate having a radially extending operating finger piece; a starter spur gear secured to the shaft, 9. starter slide plate movable tangentially of the gear wheel for engaging said gear wheel, when the switch plate is turned in one of its two directions, said engaging means including a tooth, a guide bracket slidably and pivotally supporting the outer end of the slide plate, means pivotally and slidably connecting the inner end of the slide plate to the switch plate, said switch plate having a peripheral notch defining a lifting shoulder for engaging said slide plate to move the tooth beyond the gear wheel when the switch plate is in one of its two positions, said slide plate having a wedge surface, and a finger disposed in the path of said wedge surface for moving the slide plate and the tooth into gear engaging position when the switch plate is in the other of its two positions.

5. In a starting device of the character described, a rotatable shaft, a starter wheel rotatable with the shaft, a starter slide plate movable tangentially of the starter Wheel, a guide slidably and pivotally supporting the slide plate at one end, a movable finger piece, means slidably and pivotally connecting the slide plate to the finger piece at a point remote from the guide, said slide plate engaging the starter wheel for turning the wheel upon movement of the finger piece in one direction, means moving the slide plate from out of engagement with the starter wheel at the end of the movement of the finger piece in the mentioned direction, and means for moving the slide plate in position for engaging the starter wheel when the finger piece is returned to its opposite position, and said last named means including a finger on the guide and a wedge surface on the slide plate for engagement with the finger when said finger piece is moved in the reverse direction.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,008,610 Florman July 16, 1935 2,142,256 Olander Jan. 3, 1939 2,219,552 Andis Oct. 29, 1940 2,226,697 Dalkowitz Dec. 31, 1940 2,229,939 Service et al Jan. 28, 1941 2,286,629 Kobler et a1. June 16, 1942 2,288,183 Dalkowitz June 30, 1942 

